1. Field of the Invention
The present invention relates to a driving apparatus and a recording and/or reproducing apparatus using the driving apparatus, which is preferably suited for a scanning type tunnel microscope and other apparatuses which requires a precise positioning control.
2. Related Background Art
A conventionally known fine movement driving means is structured, as disclosed in U.S. Pat. No. 3,786,332, for example, to drive a portion to be driven in such a manner that one of the piezoelectric elements provided before and after the driven portion in its driving direction is contracted while the other is extended.
As an actual driving method, such as apparatus as shown in FIG. 1 is known. In this case, a fine movement driving mechanism is constructed to sandwich a movable portion 2 by arranging in series a pair of polarized piezoelectric elements 1a and 1b having the same characteristics in forward direction. Then, while bias voltages VB in forward direction having the same intensity are applied to both piezoelectric elements 1a and 1b to extend them by the same amount, each one driving signal is amplified by two amplifiers 3a and 3b having opposite output polarity to each other to superimpose the driving signals thus obtained each having opposite phases, whereby the applied voltages are increased or decreased so that the directions in which the two piezoelectric elements 1a and 1b are extended in such an amount are made opposite to each other, thus enabling the movable portion 2 to be moved.
Nevertheless, in the above-mentioned case, unless the characteristics of the two amplifiers 3a and 3b are exactly symmetrical in their opposite polarities, there occurs a drawback that a delicate difference is generated between the driving voltages applied to both piezoelectric elements, and when one piezoelectric element 1a is extended, the other piezoelectric element 1b is not contracted equally by the same amount, for example. As a result, useless stress is given to each of the piezoelectric elements 1a and 1b, hence leading to the earlier deterioration of the piezoelectric elements 1a and 1b.